Packing for plungers.



' W. E. MoINTIRB.

PATENTED APR. 12, 1904.

" PACKING FOR PLUNGER-S.

APPLICATION FILED SEPT. 3, 1903.

H0 MODEL.

UNITED STATES.

Patented April 12, 11904.

PATET Prion.

PACKING FOR PLUNGERS.

SPECIFICATION forming part of Letters Patent No. 756,880, dated April12, 1904. Application filed September 3, 1903. Serial No. 171,788. (Nomodel.)

To all whom, it may concern:

Be it known that I, WALTER E. MOINIIRE, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented certain new and useful Improvements in Packing forPlungers; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

The present invention relates to an improvement in packing for plungers,and more particularly to an improved packing for the rods or pistons ofplunger-elevators.

Heretofore it has been common to pack plungers, pistons, and piston-rodswith packings of a form in which a part of the packing is held againstthe moving surface by the pressure of the fluid in the cylinder. Suchpackings vary in form, according as they are fixed or mounted in themoving or the fixed member of the mechanism to be packed, and are knownunder various names, as cup-leather and hat-packing. They all consist,however, of a ring of flexible material, usually partly or whollyleather, having a short cylindrical portion in contact with the movingsurface and an annular portion extending at an angle from one edge ofthe cylindrical portion by which the ring is secured in place. The otheredge of the cylindrical portion is free, and it is directed towardthedirection of pressure, so that the fluid pressing upon the outer surfaceof the cylindrical portion will hold it firmly against the movingsurface. It has been found that when the pressure of the water alone isrelied upon to hold the packingrings in contact with the moving surfacethe action of the packing is not entirely reliable, and it has thereforebeen proposed to provide mechanical means for supporting the rings. Inone proposed form of packing the cylindrical part of the rings issupported by a rigid metal ring, which is designed to leave between itsbearing-surface and the moving surface a space only equal to thethickness of the packing-ring. This arrangement is not entirelysatisfactory, however, since the packing-ring after some use wearsthinner and no longer fills the space between the moving surface and thesupporting-ring, so that the latter can no longer maintain thepacking-ring in contact with the moving surface. It has also beenproposed to pack elevator-plungers with a packing comprising a rubberring having an annular recess on its lower side, the bearing portion ofthe ring being faced by leather in the form of hat-packing. This packingacts as an automatic packing in the manner above described, and itsaction is aided by the clasticity of the rubber, which helps to maintainthe sealing portion in contact with the plunger This packing isunsatisfactory, however, owing to the fact that the pressure of therubber ring is not adjustable and is not in all cases an adequatesupport for the hat-packing. Moreover, owing to the construction of thispacking it is possible to use but one ring. Consequently some leakageoccurs at the joints where the rings are cut to permit their inser tion.

The object of the present invention is to produce a packing of the kindabove generally described having improved means for supporting thesealing part of the packing-ring, and to this end the invention consistsin the improved packing, of which the preferred embodiment is hereindescribed, and illustrated in the drawing.

The drawing illustrates by a vertical section a preferred embodiment ofthe invention as applied to the plunger of an elevator.

The construction illustrated may be described as follows: The plunger 1moves ina cylinder 2, in which is formed a stuffingrbox 3, provided witha gland 4:. An annular space 6 is supplied with lubricating material.The leather packing-rings 7, which are made in the usual hat shape, areseparated and held in place by backing-rings 8 of rubber, which are ofsuch size as to fill the space between the packing-rings and the wallsof the stuflingbox. The lower edges of the packing-rings 7 are beveledat 9'for a purpose to be presently described. The gland is adjusted bynuts 10 on studs 11, secured to the cylinder, and these parts compriseadjustable means for compressing the backing-rings 8. IVhen the packingis first installed, the gland is set up so as to compress thebacking-rings to cause them to press the packing-rings '7 firmly againstthe plunger. As the packing-rings 7 wear thinner by continued use thegland is further tightened to expand the backing-rings to compensate forthe reduced thickness of the leather. By adjusting the pressure of theelastic backing-rings the packing-rings 7 may be held against theplunger with any desired pressure, which may be kept constant byoccasional adjustment. main tight irrespective of any decrease in thepressure of the water; but upon a rise of the water-pressure, howevergreat, the joint will still be tight, for as soon as the pressure of thewater becomes greater than the pressure between the leather and theplunger, due to the pressure of the backing-rings, the water will enterbetween the leather and the backing-rings and press the leather againstthe plunger witha force proportionate to the water-pressure. This actionis facilitated by beveling the lower edges of the packing-rings, asdescribed. The constant compression of the cylindrical part of thepacking-rings maintains their entire surfaces in close contact with theplunger and prevents the excessive wear upon one side.

An advantageous feature of the present invention resides in excludingthe rubber from all contact with the moving part, so that When thepacking-rings are worn out their.replacement alone is sufficient torestore the packing to its original condition. By this means the expenseof maintenance is materially reduced.

It is to be observed that a plurality of rings of the present packingmay be employed, with the advantage of breaking joints, and thusdiminishing the liability of leakage. I

Where in the claims the term cup-ring is used it is to be understood asapplying generally to packing-rings of the form broadly described abovenamely, packing-rings of flexible material having a cylindrical portionfree at one edge and arranged to be held in contact with the movingsurface partly or wholly by the fluid-pressure in the cylinder. Bymoving surface is meant the surface having a motion relatively to thepart on Thus the joint will re' "rsasso which the packing is mounted,whether the latter be piston or cylinder.

Having thus described the invention, what is claimed is 1. A packingcomprising a cup-ring and adjustable means for maintaining the same incontact with the plunger, substantially as described.

2. A packing comprising a cup-ring and adj ustable elastic means formaintaining the same in contact with the plunger, substantially asdescribed.

3. A packing comprising a cup-ring and an elastic backing compressedagainst the outside of the cup-ring to maintain the same in contact withthe plunger, substantially as described.

4. Apacking comprising a leather cup-ring, a rubber supporting-ring, andmeans for compressing the supporting-ring against the outside of thecup-ring to maintain the same in contact with the plunger, substantiallyas described.

5. A packing for plungers, having, in combination, a cup-ring located ina stuffing-box through which the plunger passes, an elasticsupporting-ring filling the space between the cylindrical part of thecup-ring and the walls of the stuffing-box, and a gland for compressingthe elastic supporting-ring to adjust and maintain the pressure of thesame against the cup-ring, substantially as described.

6. A packing comprising a plurality of alternate leather cup-rings andsolid-rubber supporting-rings adapted to be located in a stuffing-box,and adjustable means for compressing the same, substantially asdescribed.

7 A packing comprising a cupring, an elastic sup porting-ringsurrounding the same, and adjustable means for compressing thesupporting-ring to adjust the pressure of the same against the cup ring,substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

WALTER E. MOINTIRE.

Witnesses:

HORACE VAN EVEREN, FARNUM F. DORSEY.

